Tantalum is a hard, ductile, acid-resistant, and highly conductive metal with a density of 16.65 g/cm3. Tantalum has a high melting point temperature of 3020° C. Tantalum is often used as an alloy additive and is frequently combined with niobium to increase niobium's corrosion resistance properties. When mixed with metals such as niobium, tantalum has excellent resistance to a wide variety of corrosive environments, including mineral acids, most organic acids, liquid metals, and most salts.
Niobium has physical and chemical properties similar to tantalum, including similar hardness, ductility, acid-resistance, and conductivity, although niobium is less dense (8.57 g/cm3) than tantalum (16.65 g/cm3). Niobium has a melting point temperature of 2477° C. As noted above, niobium and tantalum can be alloyed together or with other elements to make niobium-base or tantalum-base alloys. Niobium and tantalum alloys have properties suitable for a variety of applications, for example, in the aerospace, chemical processing, medical, superconducting, and electronics markets, among others.